The invention relates to a cardiac pacemaker of the type having a circuitry arrangement for varying at least one pacing parameter, in particular the pacing rate, as a function of a signal picked up in the patient's body as an input variable and correlated with physical exertion. In artificial cardiac pacemakers, it is known to perform an adaptation to physiological conditions in such a manner that a switchover of operating modes is performed in accordance with events occurring in the heart.
In addition, it was already previously known to perform these switchovers from outside as well, via external programming means (multiprogrammable pacemakers).